Emory Report
October 20, 2008
Volume 61, Number 8



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October 20
, 2008
Biophysicist wins NSF CAREER award

By carol clark

The National Science Foundation has awarded a CAREER development grant to Ivan Rasnik, assistant professor of physics, providing $500,000 over five years for his work at the interface of biology and physics, and for his efforts to bring underrepresented students into the physical sciences.

Rasnik is studying proteins that recognize and correct mismatched DNA bases, which may be involved in initiating ailments such as Huntington’s disease, by locating and tracking the movement of single protein molecules as they perform their functions.

“In physics, when you want to understand something complicated, you break it down into smaller and smaller pieces,” Rasnik says. “One approach to understand biological systems is to learn how each small piece works, so that you can better understand the whole system.”

The NSF CAREER awards go to investigators who are working on transformative ideas in their fields, while also striving to educate the next generation of scientists. Rasnik competed nationally with physicists, biologists, chemists and mathematicians for the award, funded by the NSF program “Physics of Living Systems.”

Biological physics is a relatively new field, gaining momentum a decade ago with advancements in techniques such as single molecule fluorescence resonance energy transfer (smFRET), which reveals information that cannot be detected using traditional biochemical approaches. A molecule is tagged with a dye that emits light when excited by a laser, and causes an energy transfer to a nearby dye molecule. Researchers can then indirectly observe the changes in distance between the dyes by measuring the amount of light they emit.

In collaboration with biochemist Cynthia McMurray at the Mayo Clinic, Rasnik is focused on the interactions of mismatched repair proteins with DNA triplet repeat sequences that can form hairpin structures, which may be linked to the origin of Huntington’s disease.

“Among the many questions we have about DNA triplet repeat sequences, we’d like to know how the DNA hairpins are formed,” Rasnik says. “Are there proteins that stabilize their formation?”

Rasnik involves undergraduate biology majors in his research. “The interface of physics and biology is relevant to both sides,” he says. “I want students to understand the interdisciplinary character of science.”
He will use part of the NSF grant to continue recruiting women and minority students, who are typically underrepresented in the physical sciences.

A native of Uruguay, Rasnik earned a bachelor’s of chemistry and went on to pursue a Ph.D. program in physics in Brazil, after a professor recommended him. “If you identify people who have a natural interest in science and give them just one opportunity, sometimes it can make a big difference,” he says.